摘要:
The present invention relates to a frequency shifter in an optical path containing a pulsed laser source, and it is characterized in that it comprises at least one frequency shifter (12, 13) containing an optical propagation medium, the optical path length of which is modified according to the desired frequency shift during at least one pulse among n consecutive pulses from the laser, where n≧1.
摘要:
A method for position determination with the aid of GPS satellites, including reception processing of a GPS satellite signal L2 modulated by an encrypted code Y having a key not available from the GPS satellite, so as to assess a delay of the signal L2 with respect to the signal L1 and to deduce therefrom the magnitude of the ionospheric effect so as to take account thereof and improve the accuracy of the location finding. This processing includes reducing the signal L2 to a lower band and in despreading the signal L2 by means of the non-encrypted code P produced locally in reception by a local generator of a non-encrypted spreading code P synchronized with the code Y (encrypted P) transmitted, with the aid of a phase lock loop with three parallel paths: a first path demodulated by a precise version of the locally produced non-encrypted spreading code P, a second advanced path demodulated a first time by an advanced version of the locally produced non-encrypted spreading code P and a second time by the demodulated signal of the precise path, and a third delayed path demodulated a first time by a delayed version of the locally produced non-encrypted spreading code P and a second time by the demodulated signal of the precise path, synchronization being achieved by searching for an equality of power of the carrier of the signal L2 at the output of the advanced and delayed paths.
摘要:
This invention relates to a method for treating abnormal cell proliferation in the brain by administering a compound of formula (I) or a pharmaceutically acceptable salt or hydrate thereof: ##STR1## in which R represents a hydrogen atom or an acetyl, alkoxyacetyl or alkyl radical, R.sub.1 represents a benzoyl radical or a radical R.sub.2 --O--CO-- wherein R.sub.2 represents an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, bicycloalkyl, phenyl or heterocyclylic radical, and Ar represents an aryl radical.
摘要:
The invention relates to a radiofrequency receiver, notably for satellite positioning applications, needing to operate in an environment where interference is dense, notably when it involves pulses transmitted by DME beacons. Below the useful signal suppression threshold, amplitude or power are inverted to improve the dynamic interference response time. Advantageously, the useful signal suppression threshold and the set point power or amplitude are determined by analyzing the amplitude or power probability density function in its part enriched with low amplitude/power samples.
摘要:
The invention relates to a device for measuring a Doppler frequency shift, including an optical signal channel delivering a signal light beam illuminating a reference medium; and a reference channel delivering a reference light beam for detecting the Doppler frequency shift. The frequency shift is determined from the difference in frequency between the light signal illuminating the reference medium and the light beam returned by the reference medium. The device includes at least two light radiation sources, preferably lasers, with one light radiating source generating the light beam for the signal channel and the other source generating the light beam for the reference channel.
摘要:
The present invention relates to a method of improving the integrity and safety of a system, this method making it possible, on the one hand, to detect and to locate an anomaly of a system, and on the other hand to estimate the impact of such an anomaly on the degradation of performance, with a view to attaining the safety level required and to making the data provided by this system safe, and this method is characterized in that it consists, in a system comprising sub-assemblies, in monitoring the proper operation of sub-assemblies by checking their respective transfer functions in the operational mode with the aid of stimuli dispatched to these sub-assemblies.
摘要:
The invention relates to the improving of the resistance to intentional or unintentional jamming, of a receiver of spread spectrum radio signals transmitted by polarized wave. It consists in furnishing receiver with an array antenna composed of elementary antennas having at least one so-called matched output path MP sensitive to the polarization of the polarized wave used for the transmission, certain furthermore having a second so-called cross path CP sensitive to a polarization orthogonal to that of the polarized wave used for transmission and in performing first individual antijamming processings by polarimetric filtering on each of elementary antennas with matched MP and cross CP output paths then, globally, at the level of reception signals obtained and of reception signals of elementary antennas without cross output path CP utilized, a second general antijamming processing by spatial filtering. Moreover, the invention can integrate additional antijamming processings by temporal or spectral filtering.
摘要:
The invention relates to a method of suppressing pulsed signals in particular of DME or TACAN type present in the radio signals received (Ue) by a radio-frequency receiver, characterized in that the reception frequency band of the receiver is divided into frequency sub-bands corresponding to the transmission channels of the pulsed signals, in that the presence of the pulsed signals and the transmission channel of said pulsed signals in the frequency sub-bands are detected, and in that the frequency sub-band comprising the detected pulsed signals is filtered over the duration of the pulsed signal so as to eliminate said pulsed signals pulse type.
摘要:
The invention relates to the improving of the resistance to intentional or unintentional jamming, of a receiver of spread spectrum radio signals transmitted by polarized wave. It consists in furnishing the receiver (2) with an array antenna (1) composed of elementary antennas (1a to 1f) having at least one so-called matched output path MP sensitive to the polarization of the polarized wave used for the transmission, certain (1b, 1d, 1e, 1f, 1g) furthermore having a second so-called cross path CP sensitive to a polarization orthogonal to that of the polarized wave used for the transmission and in performing first individual antijamming processings by polarimetric filtering (3) on each of the elementary antennas (1b, 1d, 1e, 1f, 1g) with matched MP and cross CP output paths then, globally, at the level of the reception signals obtained and of the reception signals of the elementary antennas (1a, 1c) without cross output path CP utilized, a second general antijamming processing by spatial filtering (4). Moreover, the invention can integrate additional antijamming processings by temporal or spectral filtering.
摘要:
A receiver for determining position based on GPS satellites and GLONASS satellites. The receiver architecture includes a radio reception chain with an antenna, frequency conversion circuits, an analogue/digital converter operating at very high rate for the GLONASS pathway, and a signal processing circuit with several general-use channels capable of receiving both GPS signals and GLONASS signals. This circuit uses a programmable pseudo-random code generator and a phase servocontrol loop which uses a local oscillator to produce a local transposed carrier frequency; this oscillator is controlled in such a way as to be able to impose a start frequency for the acquisition of a satellite signal.